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POOperator== in derived class never gets called
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  1. POOperator== in derived class never gets called
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    copied!<p>Can someone <i>please</i> put me out of my misery with this? I'm trying to figure out why a derived operator== never gets called in a loop. To simplify the example, here's my Base and Derived class:</p> <pre><code>class Base { // ... snipped bool operator==( const Base&amp; other ) const { return name_ == other.name_; } }; class Derived : public Base { // ... snipped bool operator==( const Derived&amp; other ) const { return ( static_cast&lt;const Base&amp;&gt;( *this ) == static_cast&lt;const Base&amp;&gt;( other ) ? age_ == other.age_ : false ); }; </code></pre> <p>Now when I instantiate and compare like this ...</p> <pre><code>Derived p1("Sarah", 42); Derived p2("Sarah", 42); bool z = ( p1 == p2 ); </code></pre> <p>... all is fine. Here the operator== from Derived gets called, but when I loop over a list, comparing items in a list of pointers to Base objects ...</p> <pre><code>list&lt;Base*&gt; coll; coll.push_back( new Base("fred") ); coll.push_back( new Derived("sarah", 42) ); // ... snipped // Get two items from the list. Base&amp; obj1 = **itr; Base&amp; obj2 = **itr2; cout &lt;&lt; obj1.asString() &lt;&lt; " " &lt;&lt; ( ( obj1 == obj2 ) ? "==" : "!=" ) &lt;&lt; " " &lt;&lt; obj2.asString() &lt;&lt; endl; </code></pre> <p>Here <code>asString()</code> (which is virtual and not shown here for brevity) works fine, but <code>obj1 == obj2</code> <i>always</i> calls the <code>Base</code> <code>operator==</code> even if the two objects are <code>Derived</code>.</p> <p>I know I'm going to kick myself when I find out what's wrong, but if someone could let me down gently it would be much appreciated.</p>
 

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